feat(#1137): rich unread summary in loose ends and wake signal

- hive-sh4re: UnreadMatrix gains summary: String field (per-room breakdown)
- hive-matrix-mcp/protocol: add RoomUnread struct + UnreadSummary request
- hive-matrix-mcp/handlers: collect_unread() fetches per-room data;
  single-unread rooms include truncated last-message body + sender;
  multi-unread rooms carry count only
- hive-matrix-mcp/wake: format_unread_summary() builds wake body from
  RoomUnread slice; terse one-liner for single-room/single-message,
  bulleted list for multi-room; always appends read-hint
- hive-matrix-mcp/timeline: wake body now covers all rooms with unread
  at fire time, not just the triggering event; falls back to per-event
  teaser if notification counts haven't updated yet
- hive-ag3nt/mcp: matrix_unread_summary() replaces matrix_unread_rooms();
  UnreadMatrix loose end carries per-room summary lines; render shows
  room breakdown with sender: body for single-unread rooms

hive-c0re/src/bin/hivectl.rs

@@ -501,9 +501,12 @@ fn gateway_list_users(file: &Path) -> Result<()> {
 // ---------------------------------------------------------------------------
 
 async fn agents_restart(socket: &Path, name: &str) -> Result<()> {
-    let resp = hive_c0re::client::request(socket, hive_sh4re::HostRequest::Restart {
-        name: name.to_owned(),
-    })
+    let resp = hive_c0re::client::request(
+        socket,
+        hive_sh4re::HostRequest::Restart {
+            name: name.to_owned(),
+        },
+    )
     .await
     .with_context(|| format!("connect to daemon socket {}", socket.display()))?;
     if resp.ok {